the united states led the world in a nuclear age. ever since, they have also led the effort to restrain the spread of these highly destructive weapons. with some success. in the half-century since the first atomic bomb was exploded over the desert in new mexico, nine countries have come to possess nuclear weapons. the number of countries with the capability to possess those weapons is many times more than nine. most countries which are voluntary -- voluntarily refrain from nuclear weapons, one of which is canada, have relied on the nuclear nonproliferation treaty and on american leadership. if iran gets a nuclear weapon, that could change. it could trigger an arms race in the middle east, as several countries there moved quickly to get their weapon. it is already highly volatile and very dangerous place. right now, israelis and palestinians are dying. the ancient hostility between persians and arabs remains high, as does the internal conflict between sunni and shiite muslims. that has gone on since the founding of islam. >> it was a